Looper and feed mechanism for sewing machines



Aug. 25, 1942.

LOOPER AND FEED MECHANISM FOR SEWING MACHINES Filed March 12, 1940 4 Sheets-Sheet l lNwcslgokl-th inn 2/ I f g Clarence I ATTORNEYS.

c. c. SMITH 2,294,134

C. C. SMITH Aug. 25, 1942.

LOOPER AND FEED MECHANISM FOR SEWING MACHINES Filed March 12, 1940 4 Sheets-Sheet 2 INVENTOR: Clarence C- ,Smziiy ,Z/WITNA! Edam/,5

ATTORNEYS.

C. C. SMITH Aug. 25; 1942.

LOOPER AND FEED MECHANISM FOR SEWING MACHINES Filed March 12, 1940 4 Sheets-Sheet 3 INVENTOR Clarence C. $771 11 71 BY w ATTORNEYS.

n I. I

C. C. SMITH Aug. 25, 1942.

LOOPER AND FEED MECHANISM FOR SEWING MACHINES E 5 h; 4 J E S. t 0 v. m fimfimm 5 EC V 0 w m e w w m A w n 4 a w Lg Y Lfi fi wm B 2 m m w m EN NNN %R N mm ME Patented Aug. 25, 1942 LOOPER AND FEED MECHANISM FOR SEW- ING MACHINES Clarence C. Smith, Chicago, Ill., assignor to Union Special Machine Company, Chicago, 111.,

a corporation of Illinois Application March 12, 1940, Serial No. 323,528

10 Claims.

This invention relates to looper and feed mechanism for sewing machines. More particularly, it has reference to looper and feeding mechanism for feed off the arm sewing machines of the type featured in a copending application, Serial No. 306,826, filed by Norman V. Christensen on November 30, 1939, wherein a hollow work supporting arm of angular configuration extends laterally from a base, wherein a hollow upstanding trunk or standard rises from the base to sustain a needle arm above the work supporting arm, and wherein the drive mechanism is located within the standard.

My invention has for its chief aim the provision of looper and feed mechanism for a sewing machine of the above type, which is compact for ready accommodation as a whole within the work arm; which, notwithstanding the necessity for getting around corners due to the angularity of said arm for actuation from the drive mechanism of the machine, is simple both as regards its construction and the number of moving parts involved; and in which, moreover, the interposed elements whereby the necessary movements are communicated to the looper or loopers and to the the arm sewing machine conveniently embodying my improved looper and feed mechanism.

Fig. II is a view partly in front elevation and partly in longitudinal section taken as indicated by the angled arrows IIII in Fig. I.

Fig. III is a horizontal sectional view taken as indicated by the angled arrows III-III in Fig.

II. I

on a larger scale taken as indicated by the angled arrows IVIV in Fig. III.

Fig. V is a longitudinal sectional view taken as indicated by the angled arrows V-V in Fig. III.

Fig. VI is a fragmentary sectional view taken as indicated by the angled arrows VI-VI in Figs. III and V.

Figs. VII, VIII and IX are cross sectional views through the work supporting arm of the ma- Fig. IV is a fragmentary detail sectional view angled arrows VIIVII, VIII-VIII, and IX-IX in Figs. III and V; and

Fig. X shows a front elevation of the needle head of the machine with its cover removed.

The sewing machine herein illustrated for convenience of exemplifying my invention is generally like the one disclosed in the copending patent application hereinbefore mentioned. As shown, the machine has a base I of substantially rectangular configuration from which extends horizontally at an angle, the anchorage portion 2 of a Work supporting arm 3 whereof the free end portion 4 extends substantially at right angles to said anchorage portion in the same horizontal plane, The work arm 3 is hollow with its anchorage portion 2 communicating into the hollow 5 of the base, I. From the base I rises a hollow standard 6 which sustains a horizontal needle arm I with a needle head 8 at its terminal end above the free end of the work arm 3. As viewed in plan in Fig. I, the needle arm I forms a triangle with the portions 2 and 4 of the work arm 3. The machine is arranged to be driven by a combined hand and belt wheel II at the right hand protruding end of the needle shaft I2 which extends lengthwise within 'the needle arm 'I with its left hand end terminating within the needle head 8. Secured to the needle shaft I2 is a crank disk I3, which, through a pitman I5, is operatively connected to theneedle bar I6, the latter being confined to up and down movement in the head 8 and carrying, in this instance a plurality of needles I1. The presser mechanism of the machine includes a root I8which is pivotally connected to a short presser bar I9 having sliding guidance in-a bracket 20 on a projection 2| pendant from the needle'head 8, and being urged downward by a regulatable leaf spring 22. Within the needle arm 1 at the rear and at-a level above the needle shaft I2 is a rock shaft 23; and extendingup from the presser bar I9 and into the needle head 8, is a flexible cable 25, which, at its upper end, is connectedto a crank arm 26 at the left hand end of, said rock shaft. A lever 21 extendsoutward through a clearance opening 28 in the rear side of the needle arm I (see Figs. I and .X), from'the rock shaft 23 for connection to a knee press. or foot treadle (not illustrated) whereby the presser foot may be controlled. The presser mechanism just described constitutes the subject matter of another copending application Serial No. 323,519 filed simultaneously herewith by Norman V. Christensen. Within the hollow standard 6, the needle or chine taken as indicated respectively by th'e 55 driving shaft I2 carries a pinion-30 which meshes with an idler gear 3| journaled for rotation on a stationary shaft 32, and the idler gear 3| in turn meshes with a second pinion 33, identical with the pinion 38, mounted on a short countershaft 35 joumaled crosswise in bearings 36, 31 within the base I. The cavity of the base is closed at the bottom by a cover plate 38, to form an oil-tight compartment in which the above mentioned gears operate.

Coming now to my improved looper and feed mechanism and having reference to Figs. III, 'IV and V, it will be observed that the same comprises a transmission shaft 48 which is journaled in bearing bushings 4|, 42 and 43, supported respectively by an interiorly projecting lug 45, a cross wall 46 and an end wall 41 of the work supporting arm 3, and which is driven from the countershaft 35 through a pair of intermeshing bevel gear pinions 48 and 49. At the free end of the work arm 3 in a compartment 58 set apart by a partition 5|, are located three loopers 52, which cooperate with the needles H in the usual manner. As shown, the loopers 52 are mounted in a holder 53 secured to the distal end of a looper shaft 55, which is journaled for oscillation and endwise reciprocation in bearings 56, 51 and 58 interiorly of the free end portion 4 of the work arm 3 and set respectively into the partition 5|, an upstanding bearing lug 59, and the rear side wall 68 of the anchorage portion 2 of said arm. Intermediate the bearings 51 and 58, the looper shaft 55 carries a pendant crank arm 62, which, at its lower end is connected by means of a link 63 to one extremity 64 of a rocker 65 in the form of a bell crank lever fulcrumed for oscillation on a cross pin 66 at the bottom of the anchorage portion 2 of the work arm 3. The other extremity 61 of the bell crank rocker 65 is connected by a pitman 68 with a crank or eccentric actuator 69 on the transmission shaft 48 located adjacent the bearing 42. Through the above described train of mechanism, the shaft 55 will be rocked to give the loopers their loop taking and loop shedding movements. Freely mounted on the looper shaft 55 is a. collar 18 which is held against endwise movement between a pair of thrust collars (Figs. V and DO. The collar 18 is provided with a lateral stud projection 12 which is engaged by one end of a strap link I3, the other end of which embraces an eccentric 15 on the shaft 48 within the elbow of the work supporting arm. As the shaft 48 is rotated, the eccentric I5, through this train of mechanism, will induce endwise reciprocation of the looper shaft 55, and thus impart needle avoiding movements to the loopers 52. The collar 18 is further provided with a depending lug 18 (Figs. V and IX) which has flat sides and which is'engaged between spaced guide blocks Tl at' the bottom of the free end portion 4 of the work arm 3. This guiding arrangement serves to absorb any torsion imparted to the collar 18 by the link 13.

Secured to the top of the forward end of the free end portion 4 of the work arm 3 is athroat plate I9 having needle holes, and also slots through which the toothed portions of a four motion feed dog 88 operate to engage the fabric which is being sewed in the machine, in the usual manner. The feed dog '88 is provided with 9. depending shank 8|, which, by means of a screw 82, is secured to the forward end of a feed bar 83. As shown in Figs. 1H and V, the feed bar 83 extends lengthwise within the end portion 4 of the work arm 3 above, and in the same vertical plane with the looper shaft 55. Intermediate its ends the feed bar 83 is rvotally supported by a vertical link 84 which is clevised both top and bottom and which, at its lower end, is mounted for oscillation about a pin 85 extending crosswise of the bottom of the work arm at the interior of the latter. From Fig. VIII it will be noted that the looper shaft 55 extends through the clearance opening afforded by the lower clevis of the feed bar supporting link 84. At its front end, the feed bar 83 is guided in a slot 86 in the partition 5|, and at its rear end has a longitudinal bore 81 in which a rod 88 is engaged for sliding reciprocation. This rod 88 is integral with an eccentric strap 89 which embraces an eccentric 88 immediately adjacent the eccentric 15 on the transmission shaft 48 within the elbow portion of the work arm 3. As the shaft 48 revolves, the feed bar 83 will not be afiected by the endwise components of motion of the eccentric strap rod 88, but the vertical component of this motion will cause the feed bar to oscillate about its pivotal support on the link 84 and thus impart rising and falling movements to the feed dog 88.

Pivotally connected at one end to the feed bar 83 adjacent its pivotal support is a horizontal link 9|, the other end of which is pivotally connected to a stud 92 in an arcuate slot 83 formed in a rock member 85, which is fulcrumed to swing on a cross pin 96 secured in upstanding lugs 91 interiorly of the free end portion of the work arm 3. Also pivotally connected to the rock member is one end of a pitman 88, the other end of which embraces an eccentric 99 on the transmission shaft 48. Thus during rotation of the shaft 48 the rock member 95 will be oscillated and, through the link 9| its oscillations will be converted into endwise reciprocation of the feed bar 83 for its feed and return stroke. Adjustment of the rear end of link 8| along the arcuate slot 93 in the rock member 85 will be attended by variations in the stroke of the feed bar 83 as will be readily understood from Fig. V. The arrangement of the eccentrics 15 and 98 as shown immediately adjacent opposite sides of the eccentric 98, and the corresponding links 13 and 8| respectively at opposite sides of the looper shaft 55 and the feed bar 83 is advantageous from the standpoint of symmetry and in that it favors greater compactness of the mechanism as a whole. In this connection, it will also be noted that the center of the eccentric 88, by which the feed movements are imparted to the feed bar, is arranged substantially diametrically opposite the center of the eccentric 98 by which endwise movements are imparted to the looer shaft 65. The endwise movements of the looper shaft 55 and the feed bar are opposing and balance each other to the end that the machine can be operated at high speeds without attendant vibration. It will be further observed that by disposing the eccentric actuator 69 remote from the eccentrics I5, 88 and 99 as shown, it is possible to locate the bar crank rocker 65 within the anchorage portion of the work arm, and thus avoid crowding of the parts of the mechanism in the free end portion of said arm.

The looper threads T are led from a source of supply (not illustrated) into a slot I88 formed in the top of the side wall 68 of the anchorage portion 2 of the work arm 3 which is immediately adjacent the base and through this slot are led into a recess or cavity |8| formed in said side wall beyond the slot. This recess or cavity IIII contains thread tension devices I02, and access thereto for the purpose of threading is had upon retraction of a cover I03 hinged to the side wall 60 at I05. After passing through the thread tension devices I02, the looper threads T are led through another slot I06 formed in the top of the wall 60 beyond the recess-and thence into a housing at the elbow of the work arm formed by a downwardly-swingable hinged cover I08, and in this housing there is located a suitable take-up device comprising a rotary cam I09 at the end of the transmission shaft 40 and suitable thread guiding means including a slotted plate IIII secured to the end wall 41 of the anchorage portion 2 of the work arm by a screw III and slotted stripper blade H2, together with suitable thread guiding means including a pin H3 (Fig. III) and thread eyes H5. From the take-up device the threads T are led through a longitudinal groove II 6 formed in the upper edge of the front side wall III of the free end portion 4 of the work arm 3, to the loopers 52. With particular reference to Fig. III, the above described course of the looper threads T is indicated by dot and dash lines.

The entire work arm 3, is closed at the top by a correspondingly configured angular cover plate I I8 secured thereon by screws H9, as clearly shown in Fig. I. The looper and feed mechanism is thus enclosed within an oil-tight housing in which an oil bath is maintained, the parts being automatically lubricated by splash action due to the intermittent clipping of the link 63 into the oil as clearly shown in Fig. IV. The cover plate H8 extends lengthwise of the free end portion 4 of the work arm 3 beyond its point of attachment by the screws H9 and also extends along the anchorage portion 2 of the work arm beyond its point of attachment, and along this edge it is spaced to some extent from the edge of the work arm wall to provide an opening I20 into which the looper threads T may be led for guidance to the thread slot I00.

For access to the loopers for convenience of inspection and threading, the work arm is provided at its free end with side openings which are closed by downwardly-swingable covers I2I hinged at I22 and provided at their hinges with cam surfaces I23 (Fig. VII) which engage the arms of a leaf spring I25 secured at its center to the bottom of the work arm 3 by a screw I26 and operating to yieldingly hold the covers either in open orclosed position.

Having thus described my invention, I claim:

1. In a sewing machine having a base, a hollow work arm with an anchorage portion extending laterally from the base and a free end portion in the same plane and substantially at right angles to the anchorage portion; looper and feed mechanism comprising a transmission shaft which extends lengthwise within the anchorage portion of the work arm, a looper shaft and a feed bar extending lengthwise within the free end portion of the work arm, a looper and a feed dog, respectively, at the distal ends of the looper shaft and feed bar, means on the transmission shaft at an intermediate point within the anchorage portion of the work arm for imparting oscillating movements to the loorer shaft, means at the elbow juncture between the anchorage and free end portions of the work arm for imparting endwise or needle avoiding movements to said looper shaft and for imparting endwise feed and up and down lift movements to said feed bar.

2. In a sewing machine having a hollow standard, a hollow work arm with an anchorage portion extending horizontally from the standard, and a free end portion inthe same plane extending substantially, at right angles to the anchorage portion, a needle arm extending from the standard above the work arm, and drive mechanism within the standard; looper and feed mechanism comprising a transmission shaft which extends lengthwise within the anchorage portion of the work arm and which derives its motion from the drive mechanism, a looper shaft and a feed bar extending lengthwise within the free end portion of the work arm, a looper and a feed dog respectively at the distal ends of the looper shaft and feed bar, means on the transmission shaft at an intermediate point within the anchorage portion of the work arm for imparting oscillating movements to the looper shaft, and means at the elbow juncture between the anchorage and free end portions of the work arm for imparting endwise or needle avoiding movement to the looper shaft and for imparting endwise feed and up and down lift movements to the feed bar.

3. In a sewing machine having a hollow standard, a hollow work arm with an anchorage portion extending horizontally from the standard and a free end portion in the same plane extending substantially at right angles to the anchorage portion, a hollow needle arm extending horizontally from the standard above the work arm, a needle actuating shaft within the needle arm, a counter shaft extending crosswise of the bottom of the standard and a train of gears connecting the needle actuating shaft with the counter shaft, looper and feed mechanism comprising a transmission shaft which extends lengthwise within the anchorage portion of the work arm and which derives its motion from the counter shaft aforesaid, a looper shaft and a feed bar extending lengthwise within the free end portion of the work arm, a looper and a feed dog, respectively, at the distal ends of the looper shaft and the feed bar, means on the transmission shaft at the elbow juncture between the anchorage and free end portions of the work arm for imparting endwise or needle avoiding movements to the looper shaft, and for imparting endwise feed and up and down or lift movements to the feed bar, and means at an intermediate point within the anchorage portion of the work arm and actuated from the transmission shaft for imparting oscillating movements to the looper shaft.

4. Looper and feed mechanism for a sewing machine according to claim 1, wherein the means for imparting the oscillating movements to the looper shaft includes a rocker in the form of a bell crank fulcrumed on an axis extending transversely of the anchorage portion of the work arm, a rotary actuator on the transmission shaft connected to one extremity of the rocker, and a crank arm on the looper shaft connected to the other extremity of the rocker.

5. Looper and feed mechanism for a sewing machine according to claim 1, wherein the means for imparting the oscillating. movements to the looper shaft includes a rocker in the form of a bell crank fulcrumed on an axis extending transversely of the anchorage portion of the work arm below the transmission shaft, a pitman pendant from a rotary actuator on the transmission shaft and connected to one extremity of the bell crank rocker, and a pendant crank arm on the looper shaft connected to the other extremity of the bell crank rocker.

6. Looper and feed mechanism 'for a sewing machine according to claim 1, wherein the means for imparting the endwise movement to the looper shaft and the feed and lift movements to the feed bar include a group of contiguously arranged rotary actuators on the transmission shaft, and the means for oscillating the looper shaft includes a rotary actuator on the transmission shaft within the anchorage portion of the work arm remote from the aforesaid group of rotary actuators.

'I. Looper and feed mechanism for a sewing machine according to claim 1, wherein the feed bar is plvotally supported intermediate its ends at the top of a vertical link, which, at the bottom is fulcrumed on a transverse pin; wherein the looper shaft lies in the same vertical plane with the feed bar and passes through a clearance opening in the link; and wherein the means for imparting the lift movements to the bar includes a rotary actuator on the transmission shaft having a strap with a projection in longitudinal sliding engagement with the rear end of the feed bar.

8. Looper and feed mechanism for a sewing machine according to claim 1, wherein the feed bar is pivotally supported intermediate its ends at the top of a vertical link, which, at the bottom is fulcrumed on a transverse pin; wherein the, looper shaft lies in the same vertical plane with the feed bar and passes through a clearance opening in the link; and wherein the means for imparting the endwise or feed movements to the feed 'bar includes a rocker fulcrumed on a cross pin in the bottom of the work arm, a horizontal forwardly-extending link connecting the feed bar to the rocker, and a rearwardly-extending connection engaged with a rotary actuator on the transmission shaft.

9; Looper and feed mechanism for a sewing machine according to claim 1, wherein the looper shaft and the feed bar are positioned one above the other; wherein the feed bar receives its rise and fall movements from a rotary actuator on the transmission shaft in line with the feed bar and connected with the rear end of the latter; wherein there is a rotary actuator on the transmission shaft immediately adjacent each side of the first mentioned rotary actuator; and wherein connections extend forwardly within the free end portion of the work arm respectively from the last mentioned rotary actuators at opposite sides of the feed bar and are connected respectively to the looper shaft and said feed bar to communicate endwise movements to them.

10. Looper-and feed mechanism for a sewing machine according to claim 1, wherein the looper shaft and the feed bar are positioned one above the other; wherein the feed bar receives its rise and fall movements from a rotary actuator on the transmission shaft in line with the feed bar and connected with the rear end of the latter; wherein there is a rotary actuator on the transmission shaft immediately adjacent each side of the first mentioned rotary actuator; wherein connections extend forwardly within the free end portion of the work arm respectively from the last mentioned rotary actuators at opposite sides of the feed bar and are connected respectively to the looper shaft and said feed bar to communicate endwise movements to them; wherein a fourth rotary actuator is mounted on the transmission shaft remote from the contiguously arranged other actuators; and wherein connections extend forwardly in the anchorage portion of the work arm from said fourth rotary actuator to communicate oscillatory movements to the looper shaft.

CLARENCE C. SMITH. 

